JPS6134595B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing simultaneous closing of multiple shutoff valves. Specifically, when multiple devices each equipped with shutoff valves on the upstream and downstream sides of a fluid flow path are arranged in parallel, the shutoff valve for each flow path is prevented from closing all the flow paths at the same time. and relates to a device for ensuring that at least one piece of equipment is in working condition.

For example, in oil refining and chemical industry plants, multiple pieces of equipment are arranged in parallel, some are operated and others are stopped, and when the need arises, the equipment can be switched by operating shutoff valves. , work such as repairs and catalyst regeneration is often carried out without stopping plant operations.

To operate the above shutoff valves, first open the shutoff valves installed upstream and downstream of the equipment that was previously inactive, then close the shutoff valves installed upstream and downstream of the equipment that is about to go into hibernation. It is normal to follow these steps. This operation itself is not difficult, but in plants where many pipes come and go and there are many valves, it may happen that other valves are opened without opening the valve that should be opened, or that valves that should be kept open are opened. It is possible to accidentally close it.

Such erroneous operation is especially fatal for safety valves among various types of equipment. This is easily understood if you consider that a safety valve is a device that operates when an abnormality occurs in a plant and the internal pressure rises abnormally, releasing the pressure and preventing the plant from being destroyed. Will.

The relationship between safety valves and shutoff valves attached to pressure vessels is stipulated as follows.

“If a device is installed that is equipped with two or more safety valves and cannot be closed at the same time, a closing device (stop valve) is installed between the pressure vessel and the safety valve.
It is okay to set up ” (December 25, 1960,
(Basic No. 1429) Therefore, measures such as wrapping a chain around the handle of a valve that must be kept open so that it cannot be closed are taken, but this is very
There is a chance that an erroneous operation will occur when the chain is removed for switching, so this is not a sufficient countermeasure.

A method was also devised to prevent erroneous operation by converting the handle into gears and directly connecting the shutoff valves whose opening and closing should be linked. Although this method can prevent erroneous operation, it has the disadvantage that the position of the shutoff valve is definitely restricted.

The present invention was made with the intention of solving these problems.

The simultaneous closure prevention device for multiple shutoff valves of the present invention arranges two or more sets in parallel, each consisting of a fluid handling device and a shutoff valve provided on its upstream and downstream sides, and opens and closes the shutoff valves. In a device in which the flow path can be switched, each shutoff valve is configured so that it can be opened and closed only by operating multiple types of keys,
The keys required to open and close two shutoff valves in the same flow path are different from each other, and are common to the keys required to open and close two shutoff valves in other flow paths.
The plural types of keys required to open and close the shutoff valves are characterized in that they are all combined in different combinations, so that at least one type of key is always used.
The configuration is such that each of the shutoff valves is maintained in an open state.

When installing a safety valve in a plant, if it is open to the atmosphere, a shutoff valve is placed only on the inlet side, but if it is connected to a flare header, a shutoff valve is often placed on the outlet side as well. Therefore, if we illustrate the difference between suitable and unsuitable depending on the state of the shut-off valve in this case,
As shown in Figure 1. That is, case ~ is suitable, and other states, such as case, are unsuitable. (In the figure, the symbol of the shutoff valve with a hollow symbol indicates the open state, and one with a filled symbol indicates the closed state.) The embodiment of the present invention will be explained by taking as an example the case where the equipment in the flow path is a safety valve. This will be explained with reference to FIGS. 2 to 4.

These diagrams show two channels with safety valves.
This figure shows a case where two shutoff valves are provided and they are opened and closed using four types of keys: A, B, C, and D.

In FIG. 2, shutoff valves V-A1 and V-A2 of flow path A are open, and locks A1 and A2 are open.
locks them and keeps them open. Lock A1 is operated with keys I and B, and lock A2 is operated with keys H and D, respectively. Shutoff valves V-B1 and V-B2 in flow path B are closed and locks B1 and B2 do not lock them.
Lock B1 is key and D, and lock B2 is
are operated using keys H and B respectively.

When the lock does not lock the shut-off valve, the key is trapped by them and cannot be removed.

Now, when trying to switch the flow path from A to B, in order to satisfy the condition that neither flow path is closed at the same time, first open flow path B, then switch to flow path A.
must be closed. Therefore, as shown in FIG. 3, the shutoff valves V-B1 and V-B2 of flow path B
open.

Next, as shown in FIG. 4, the shutoff valves V-B1 and V-B2, which were just opened, are locked in the open state,
Extract key, d, c, and b. Then, insert these keys into locks A1 and A2 to open the locks and open the shutoff valves V-A1 and V-A2.
Make it movable and put it in the closed state. This completes the channel switching.

As can be understood from the above explanation, when the shutoff valve is opened, the key is trapped in the lock and cannot be removed, and when the shutoff valve is opened, the trap is released and the key can be removed. Then, by using this extracted key to unlock the other shutoff valves so that they can be closed for the first time, the shutoff valves in one of the flow paths will always be in the open state. .

The principles described above can also be applied when the number of channels exceeds two. In the case of three channels, for example, the fifth
Adopt the key combination shown in the diagram. In this way, two of the channels A, B, and C (B and C in the illustrated example) are always locked in an open state. The shutoff valve for each flow path is
It is opened and closed using four types of keys: B, C, and D, but you will notice that no two keys have the same combination.

If this is expanded further, it will be possible to handle any increase in the number of channels. Figure 6 shows that when applied to 10 channels, 2 keys each of 3 types from 6 types from A to 6 are used.
An example of selecting a set and using it to open and close shutoff valves at the front and rear of equipment is shown below.

The mechanism for locking the shutoff valve in the open state is arbitrary, but as an example, the lock structure shown in FIGS. 7 and 8 is recommended.

FIG. 7 shows a state in which the lock bar 2 is advanced from the lock body 1, making it impossible to rotate the shutoff valve handle. The position of the lock bar is fixed by a stopper rod 3. In this state, the key is removed, and unless the key is inserted, the lock bar will not move and the shutoff valve will remain open.

When the key 4 is inserted and pressed, the stopper rod 3 springs up and the lock bar 2 can be moved back, as shown in FIG. As the lock bar 2 retreats, the handle of the shutoff valve becomes rotatable and can be closed. In this state, key 4
I can't get over it. The mechanical configuration for realizing the above operations is well known in the lock technology field.
Just adopt it.

The lock can be installed at any position, and a support may be provided if necessary, but normally it will be sufficient to fix it to the yoke or bonnet of the shutoff valve body.

According to the present invention, no matter what positional relationship the shutoff valves have, for example, even if they are installed at a considerable distance, simultaneous closing of the flow paths can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing suitability and unsuitability depending on the open/closed state of the shutoff valve when two safety valves having shutoff valves on both the inlet side and the outlet side are arranged in parallel.
is suitable and is an example of inappropriate. 2 to 4 are conceptual diagrams for explaining one embodiment of the present invention, in which flow path A is open and flow path B is closed, and FIG. 3 is a flow path A. and flow path B both open,
FIG. 4 shows a state in which flow path A is closed and flow path B is open. FIG. 5 is a conceptual diagram corresponding to FIG. 2, showing an example in which the present invention is applied to three channels. FIG. 6 is an explanatory diagram showing an example of key combinations when the present invention is applied to 10 channels. 7 and 8 show an example of a locking means suitable for embodying the device of the present invention, in which FIG. 7A is a longitudinal cross-sectional view with the lock bar advanced and locked; B is I of A
FIG. 8A is a cross-sectional view in the -I direction, and FIG.
A vertical sectional view corresponding to Figure A, Figure 8B is a - of A.
FIG. V-A1, V-A2, V-B1 and V-B2
...Shutoff valve, A1, A2, B1 and B2...Lock, 2...Lock bar, 4...Key.

Claims (1)

[Claims] 1. Two or more sets consisting of a fluid handling device and shutoff valves provided on the upstream and downstream sides thereof are arranged in parallel, and the flow path can be switched by opening and closing the shutoff valves. In such a device, each shutoff valve is configured so that it can be opened and closed only by operating multiple types of keys, and the keys required to open and close two shutoff valves in the same flow path are different from each other. This is the same key that is required to open and close the two shutoff valves in other flow paths.
The plurality of types of keys required to open and close one shutoff valve are characterized by having different combinations of keys, so that at least one shutoff valve is always kept open. A device to prevent simultaneous closing of multiple shutoff valves. 2. The simultaneous closure prevention device according to claim 1, wherein the device handling fluid is a safety valve.